Online charging management server

ABSTRACT

An online charging management server comprising: receiving means arranged to receive at least one account request message transmitted from a network service provider; and transmitting means arranged to transmit an online account balance message to a further separate server based on the received account request.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an online charging server, and moreparticularly but not exclusively to an online charging server for theprovision of prepay functions for wireless cellular networks.

2. Description of the Related Art

A communication system is a facility that enables communication betweentwo or more entities such as user terminal equipment and/or networkentities and other nodes associated with a communication system. Thecommunication may comprise, for example, communication of voice,electronic mail (email), text messages, data, multimedia and so on.

The communication may be provided by a fixed line and/or wirelesscommunication interfaces. A feature of wireless communication systems isthat they provide mobility for the users thereof. An example ofcommunication systems providing wireless communication is a public landmobile network (PLMN). An example of the fixed line system is a publicswitched telephone network (PSTN).

A communication system typically operates in accordance with a givenstandard or specification which sets out what the various elements of asystem are permitted to do and how that should be achieved. For example,the standard or specification may define if the user, or more preciselyuser equipment, is provided with a circuit switched server or a packetswitched server or both. Communication protocols and/or parameters whichshould be used for the connection are also typically defined. Forexample, the manner how communication shall be implemented between theuser equipment and the elements of the communication networks istypically based on a predefined communication protocol. In other words,a specific set of “rules” on which the communication can be based needsto be defined to enable the user equipment to communicate via thecommunication system.

The introduction of Third Generation (3G) communication systems willsignificantly increase the possibilities for accessing services on theInternet via mobile user equipment (UE) as well as other types of UE.

Various user equipment (UE) such as computers (fixed or portable),mobile telephones, personal data assistants or organizers and so on areknown to the skilled person and can be used to access the Internet toobtain services. Mobile user equipment referred to as a mobile station(MS) can be defined as a means that is capable of communication via awireless interface with another device such as a base station of amobile telecommunication network or any other station.

The term “service” used above and hereinafter will be understood tobroadly cover any service or goods which a user may desire, require orbe provided with. The term also will be understood to cover theprovision of complimentary services. In particular, but not exclusively,the term “service” will be understood to include Internet protocolmultimedia IM services, conferencing, telephony, gaming, rich call,presence, e-commerce and messaging e.g. instant messaging. A “service”may comprise two or more parts. For example, a video telephone servicecomprises a voice part and a video part. Alternatively two or moreservices may be provided at the same time, for example a gaming serviceand a chat room service may be provided at the same time.

The 3G Partnership Project (3GPP) is defining a reference architecturefor the Universal Mobile Telecommunication System (UMTS) core networkwhich will provide the users of user equipment UE with access to theseservices. This UMTS core network is divided into three principaldomains. These are the Circuit Switched domain, the Packet Switcheddomain and the Internet Protocol Multimedia (IM) domain.

The latter of these, the IM domain, makes sure that multimedia servicesare adequately managed. The IM domain supports the Session InitiationProtocol (SIP) as developed by the Internet Engineering Task Force(IETF).

One aspect of management relevant for both IMS and non IMS systems (i.e.services provided to subscribers via service nodes outside the corenetwork, e.g. multimedia messaging and location estimation services), isthat of charging users for supply of services. Charging can be dividedinto two modes of charging. The first is on-line charging which is wherethe user effectively pre-pays for a service and the second is off-linecharging where a user is billed for a service after the session. Thusthe first charging method is implemented by pay-as-you-go systemswhereas the second method is implemented where the user is billed atregular intervals for calls which the user has made.

Currently for on line charging any network function wishing to charge auser is required to pass a Credit Control Request message to a networkelement known in the art as an Online Charging System (OCS). Attempts tostandardise the OCS architecture has been defined in standards such atthe third generation partnership project (3GPP) technical specification(TR) 32.815. Furthermore the applications and some interfaces operatedby the OCS have furthermore been standardised by 3GPP TS 32.296.

The architecture of the OCS as currently implemented within thesestandards has problems for any operator attempting to operate a unified(i.e. online and off line) billing system. As defined by the abovestandards the OCS contains an account database which is operated on byan account balance management system. The account balance managementsystem and account database within the OCS is effectively a partialduplication of information held by the operator for the off lineaccounting system.

SUMMARY OF THE INVENTION

It is an aim of the invention, and embodiments thereof, to provide animprovement to online accounting systems which offer the possibility ofcreating centralised accounting operating such systems.

There is provided according to the invention an online chargingmanagement server comprising: receiving means arranged to receive atleast one account request message transmitted from a network serviceprovider; and transmitting means arranged to transmit an online accountbalance message to a further separate server based on the receivedaccount request.

The online account balance message may be an online account balancerequest message.

The online account balance request message may comprise a request for atleast one of: Make a reservation; Commit reservation and make newreservation; Commit reservation; Release reservation; Balance query;Increase balance; and Decrease balance.

The receiving means may be further arranged to receive an online accountbalance message from the further server.

The online account balance message from the further server may be anonline account balance answer message.

The online account balance answer message may comprise a value based onthe online account balance request message.

The online account balance message may be a Diameter message.

The online account balance message may be a Diameter credit controlmessage.

The server may be a rating server.

According to a second aspect of the present invention there is providedan online charging account management server comprising: receiving meansarranged to receive an online account balance message from at least onefurther separate server, the online account balance message based on areceived account request message transmitted from a network serviceprovider; and processing means arranged to perform an online accountbalance action based on the received online account balance message.

The server may further comprise transmitting means arranged to transmitan online account balance message to the further server.

The online account balance message may be an online account balancerequest message.

The online account balance request message may comprise a request for atleast one of: Make a reservation; Commit reservation and make newreservation; Commit reservation; Release reservation; Balance query;Increase balance; and Decrease balance.

The online account balance message transmitted to the further server maybe an online account balance answer message.

The online account balance answer message may comprise a valuedetermined by the processing means based on the performed action.

A system may comprise: the online charging management server asdescribed above; and the separate online charging account managementserver as described above.

There is provided according to a third aspect of the present invention amethod for performing online charging within a communications networkcomprising an online charging management server and a separate onlinecharging account management server, the method comprising the steps of:receiving at the online charging management server at least one accountrequest message transmitted from a network service provider; andtransmitting from the online charging management server to the separateonline charging account management server an online account balancemessage based on the received account request message.

The method may further comprise the steps of: receiving at the separateonline charging account management server the online account balancemessage; and performing at the separate online charging accountmanagement server at least one account management function based on thereceived online account balance message.

The method may further comprise the step of transmitting from theseparate online charging account management server to the onlinecharging management server an online account balance message on thebasis of the step of performing the at least one account managementfunction.

According to a fourth aspect of the present invention there is provideda computer program product arranged to carry out the method forperforming online charging within a communications network comprising anonline charging management server and a separate online charging accountmanagement server, the method comprising the steps of: receiving at theonline charging management server at least one account request messagetransmitted from a network service provider; and transmitting from theonline charging management to the separate online charging accountmanagement server an online account balance message based on thereceived account request message.

The computer program product may further carry out the steps of:receiving at the separate online charging account management server theonline account balance message; and performing at the separate onlinecharging account management server at least one account managementfunction based on the received online account balance message.

The computer program product may further carry out the step oftransmitting from the separate online charging account management serverto the online charging management server an online account balancemessage on the basis of the step of performing the at least one accountmanagement function.

According to a fifth aspect of the present invention there is provided acombined online and offline charging server comprising: an onlinecharging account management server comprising: receiving means arrangedto receive an online account balance message from at least one furtherseparate server, the online account balance message based on a receivedaccount request message transmitted from a network service provider; andprocessing means arranged to perform an online account balance actionbased on the received online account balance message; and an offlinecharging account management server.

BRIEF DESCRIPTION OF THE FIGURES

The invention is described by way of example only with reference to theaccompanying figures in which:

FIG. 1 shows a simplified view of a communications network containing aconventional online charging system;

FIG. 2 shows a simplified view of an improved online charging system inwhich the invention and embodiments thereof may be implemented; and

FIG. 3 to 8 show flow diagrams demonstrating the operation of theimproved online charging system for a range of accounting operations.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is described herein by way of example with reference to anumber of embodiments.

Reference is made to FIG. 1 which shows schematically a system in whichembodiments of the invention can be implemented. The system comprisesuser equipment 2. The user equipment 2 can take any suitable form andmay for example be a mobile or fixed entity such as a mobile telephone,personal digital assistant (PDA), portable computer, laptop computer,fixed computer or any other suitable device. The user equipment 2 isarranged to communication with a radio access network (RAN) 8 via awireless connection. This wireless connection may be at any suitablefrequency, such as for example a radio frequency.

The radio access network 8 generally consists of a base station entity(sometimes referred to as node B). For the purpose of this document, theterm base station will be used and is intended to cover any suitableentity. The radio access network 8 also comprises a control element.Depending on the standard, the control element can be referred to as aradio network controller (RNC) in the case of a UMTS system or a basestation controller (BSC) in the case of a GSM system. It is intendedthat the term controller cover any such control entity. In somearrangements, the control function is provided separately from the basestation function and a single control entity may control a number ofbase stations. In other embodiments of the present invention, each basestation may incorporate part of the control function.

The radio access network is arranged to communicate with a core network10. The core network 10 illustrated in FIG. 1 is a packet switched corenetwork. The core network comprises at least one serving GPRS (generalpacket radio service) support node SGSN which is used to switch thepacket switched transactions and at least one GPRS support nodes GGSNwhich are switches at the point where the core network 10 is connectedto external packet switched networks.

The core network is connected to an IM (IP multi-media) subsystem 14. AGGSN is connected to a P-CSCF 16 (proxy call session control function)in the IMS 14. The P-CSCF is connected to a serving S-CSCF 24. TheS-CSCF contacts an interrogating I-CSCF 22 in the terminated network.The I-CSCF 22 is arranged to determine the appropriate serving-CSCF (S)24 for the end user that is the called party.

FIG. 1 shows a calling party. The called party may be connected to adifferent or the same IMS. Likewise, the called party may be connectedto the same or a different OCS. Where the called party is connected to adifferent IMS, a different core network and RAN are provided. Where theIMS is the same, different core networks may or may not be required.Likewise, the RAN may be the same or different for the called party tothat of the calling party.

Although for the purpose of simplifying the explanation of the inventionin the above example the IMS 14 is shown connecting to the OCS 6 itwould be understood by the person skilled in the art that the OCS 6 isalso capable to operating with other non IMS network elements.Specifically 3 GPP specifies three types of protocol messages capable ofcommunicating messages to the OCS 6. The first type of message, shown inFIG. 1, is the IMS online charging reference point defined in the 3 GPPspecifications by the R₀ interface. The second type of message, notshown in FIG. 1, is for on-line charging reference points for non IMSservices such as from Multimedia messaging services, WLANs, and GatewayGPRS serving nodes (GGSNs) which are defined within the 3 GPPspecifications as the R₀ interface. The third type of message, also notshown in FIG. 1 but specified in the 3 GPP specifications are theCustomised Application for Mobile network Enhanced Logic (CAMEL)Application Part (CAP) message which can be transmitted from networkelements such as the Mobile Switching Centre (MSC) and Serving GPRSserving node (SGSN).

With reference to FIG. 2 an improved OCS 106 is shown. The improved OCS106 comprises at least two physically separate servers. The first serveris an account balance management server 103 and the second server is thecharging and rating server 101.

The account management server, also known as an account balancemanagement server 103 comprises an account balance management functionarranged to transmit and receive messages to and from the charging andrating part. Furthermore the account balance server 103 comprisesaccount data 111 capable of being accessed by the account balancemanagement function.

The account balance server is further arranged to be connected to arecharging server 3. The recharging server is used to recharge theaccount values stored by the account data 111. Thus for example when auser account is low in terms of credit, where credit is for examplecurrency, bandwidth air time, or data transmission availability, therecharging server can pass a message to the account balance managementserver 103 to ‘top up’ the account in question.

The charging and rating server, also known as an online chargingmanagement server, comprises an online charging function (OCF) 151, acharging gateway function 161, and a rating function 171. The OCF itselfcomprises a session based charging function 153 which as known in theart is used to perform IMS session charging on the receipt of an creditcontrol messages from a IMS Call session control function (CSCF), and aevent based charging function 155 which performs event based chargingusing the R₀ or R₀′ interface credit control messages. Although notshown in FIG. 2, the OCF 151 can in further embodiments comprise abearer based charging function. The bearer based charging function isarranged to perform bearer based charging using the CAP protocol messagetype.

The charging gateway function 161 which is connected to the OCF 151 andthe operator's post processing system 5, is used by the OCF 151 togather and transmit charging information to the operator post processingsystem 5.

The rating function 171 is connected to the OCF 151 and is used by theOCF 151 to derive tariffs and rates of the available services. Thefunctionality of the rating function 171 is well defined in 3GPP TR32.815 as being one of unit determination, calculation and reservationof a number of session related non-monetary units (service units, datavolume, time and events), price determination (calculation of monetaryunits for a given number of non-monetary units, tariff determination(determination of tariff information based on the subscriberscontractual terms and service being requested), and get/set countersapplicable for rating.

With regards to the interaction of the account balance management server103 and the charging and rating server 101, a pair of account balancerequest (ABR) and account balance answer (ABA) messages are disclosedhereafter.

A template for an ABR message is shown below

ABR: <Session-Id> {-Normal routing based information as in Diameterbase-} { Account-Balance-Action} { Account-Balance-Request-Number} {User-Name/Account-Id} [ Requested-Service-Unit] [ Used-Service-Unit]

where the field <session-Id> is a unique session number provided by theOCF 151, the field {Account-Balance-Action} represents the actionrequested from the account balance management server 103. The field{Account-Balance-Request-Number} is a number identifying this specificrequest from the charging and rating server 101 to the account balancemanagement server 103. The field {User-Name/Account-Id} is theidentifier linking the user requesting the service to the account codestored within the account balance management server 103. The field[Requested-Service-Unit] identifies the service providing networkelement from which the user has requested a service. The field[Used-Service-Unit] identifies any service providing network elementwhich has already provided the user with a service.

and a template for an ARA message is shown below.

ABA: <Session-Id> {-Normal routing based information as in Diameterbase-} { Account-Balance-Action} { Account-Balance-Request-Number} {User-Name/Account-Id} [ Granted-Service-Unit]

the only additional field being that of the [Granted-Service-Unit] whichis the identifier identifying a value which has been determined by theaccount balance management server 103 based on the action carried out byaccount balance management server.

Furthermore the Account-Balance-Action AVP field has the followingvalues:

-   1 Make reservation-   2 Commit reservation and make new reservation-   3 Commit reservation-   4 Release reservation-   5 Balance query-   6 Increase balance-   7 Decrease balance

In separating the online charging server into online charging managementand online charging account balance management servers which communicateby means of the above described messages then it is possible toincorporate the functionality of the online charging account balancemanagement server into a combined online and offline account balancemanagement server and therefore overcome the problems of account anddata duplication between users with online and offline accounts.

The operation of the account and balance management server 103 onreceipt of these values will be further disclosed with respect to FIGS.3 to 9 below. The examples described with respect with these figurescomprise the simplified network architecture of the user equipment 2, anetwork element 51 (which in the example provided by FIG. 1 would bewithin the IMS 14 but equally can be any of the network elementsdescribed earlier), the OCF 151 and the account balance managementserver 111.

With respect to FIG. 3, a first example of the use of these accountbalance request (ABR) and account balance answer (ABA) messages is shownfor a standard service operation and termination. The first step 201occurs when the UE 2 transmits an initial service request to the networkelement 51.

The next step 203 occurs when the network element 51 transmits a creditcontrol request initialisation message to the OCF 151. The creditcontrol message initialisation message is sent in order to determine ifthe user has sufficient credit for the service requested and to requeston-line payment.

In the next step 205 the OCF 151 transmits an ABR Reserve message (i.e.an ABR message with an Account-Balance-Action AVP field set to 1) to theaccount balance management server (ABMS) 103.

On receipt of this message the ABMS 103, in the next step 207, examinesthe account information and if there is sufficient credit within theaccount makes a credit reservation in the account. A credit reservationeffectively ring fences a predetermined amount of credit from being useduntil the reservation is removed. As described previously this creditcan be monetary in nature, or can be network dependent, e.g. bandwidth,data, event count related. In the following examples described hereafterthe credit is monetary in nature.

After making this credit reservation, the ABMS 103 transmits in step 209an ABA message back to the OCF 151 acknowledging that the reservationwas successful.

The OCF 151 then calculates (using the rating function not shown in FIG.3), the number of units which relate to the service which the user canobtain using the reserved monetary value. Thus for example if theservice is on demand video measurable in terms of kB of data receivedand rated at F euros per kB received, with the reserved monetary valuebeing G euros per reservation then the OCF calculates that eachreservation is able to provide G/F kB of video before the reservation isexhausted.

The OCF then transmits, in step 213, to the NE 51 a credit controlanswer message containing a value of the number of units available tothe user for the supply of this service. Once the NE 51 receives thismessage the NE then starts to supply the service to the UE 2.

If the user operating the UE 2 wishes to end the service before all ofthe allocated units are exhausted the steps 215 to 227 describe theprocess used in the present invention to account for the remaining unitvalue.

Step 215 occurs when the UE 2 transmits to the NE 51 a servicetermination request. The NE 51 after receiving the termination requestcalculates the remaining units and in step 217 transmits to the OCF 151a CCR termination message, the message contains the remaining unitvalue.

The OCF 151 on receiving the remaining unit value, calculates in step219 the reverse calculation of step 211 to determine remaining creditvalue is, which for the above examples is a euro currency value.

The OCF 151 then transmits to the ABMS 103 an ABR Commit message, (i.e.an ABR message with an Account-Balance-Action AVP field set to 3).Within the message the currency remaining value from the reserved amountis also passed.

The ABMS 103 then in step 223 examines the credit reservation andreturns to the active account value the remaining value, effectivelyrefunding the partially unused reserved currency.

In the following step 225 the ABMS 103 transmits to the OCF 1512 an ABAmessage informing the OCF 151 that the commit procedure succeeded.

In a further step 227 the OCF 151 transmits to the NE a further CCAmessage confirming at the NE 51 that the commit charge has beencredited.

With respect to FIG. 4, a second example of the present invention isdescribed where the units supplied by the OCF 151 are exhausted beforethe service is terminated.

The first six steps 201 to 213 of the second example follow the sameprocedure as that described in the first six steps of the previousexample describing the initialisation of the service.

When the reserved and converted units have been exhausted whilst theservice is continued then in step 301 the NE 51 determines that newunits are required to continue the operation of the service.

In the next step 303, the NE 51 transmits to the OCF 151 a CCR updatemessage.

The OCF 151 on receiving the CCR update message performs a rating andconversion operation to convert the used units into the monetaryequivalent. This step 305 is a similar operation to that performed bystep 219 of the first example, the only difference being that the valuereturned is equal to the amount originally reserved.

The OCF 151 in the step following the calculation transmits to the ABMS103 an ABR commit and reserve message (i.e. an ABR message with anAccount-Balance-Action AVP field set to 2).

The ABMS 103 on receipt of the ABR commit and reserve message thenperforms in step 309 the actions of committing the used credit from thereserved account and a creation of a further reservation.

In the next step the ABMS 103 transmits to the OCF 151 an ABA messagecontaining the value of the reserved amount.

In the following two steps 211 a, and 213 a the OCF 151 performs aconversion of credits to units operation similar to that carried out instep 211 followed by the transmission of a CCA message to the NE 51. TheCCA message received at the NE 51 is similar to the message sent in step213 where the message contained the determined number of units. Theservice at the end of this procedure can now be continued until it isterminated by the user as described in the first example as shown inFIG. 3 steps 215 onwards, or the further units are exhausted and the NErequests a further update with a repetition of steps 303 onwards.

With respect to FIG. 5 a further example of the present invention isdemonstrated whereby the user initially requests a service but does notactually use any of the units transferred to the NE 51.

The first six steps 201 to 213 of the third example are the same as thefirst six steps 201 to 213 of the first and second examples showing theinitialisation of the service.

In the next step 215 the UE 2 transmits to the NE 51 a servicetermination request. In step 401 the NE 51 determines that the servicedid not use any units. As described above with respect to the previousservice termination sequence and referenced by the step 217, the NE 51transmits to the OCF 151 a CCR termination message.

The OCF 151 on receiving a CCR termination message calculates in step403, the amount of monetary credits used. This step is similar to steps219 and 305 of the previous examples except in this example there arezero used units and therefore the amount of monetary credits used istherefore also zero.

The OCF 151, on detecting that zero units were used transmits, in step405, an ABR release message (i.e. an ABR message with anAccount-Balance-Action AVP field set to 4) to the ABMS 103.

The ABMS 103 in step 409, having received the ABR release messagereleases the reservation. This in effect returns the credit that hadbeen ring fenced in step 207 to the active account.

The ABMS 103 then in step 411 transmits to the OCF 151 an ABA messageacknowledging that the reservation release was successful.

The OCF 151 then in step 413 transmits to the NE 51 a CCA messageinforming the NE that the termination accounting process was successful.

With respect to FIG. 6, a further example of the present invention isshown where the user operating the UE 2 wishes to see the value of theusers current account balance.

In step 501 the UE 2 transmits to the NE 51 a balance inquiry message.

In step 503 the NE 51 on receipt of the balance inquiry requesttransmits to the OCF 151 a CCR Event message. The event message containsan indicator that the account balance for the user should be read.

In step 505 the OCF transmits to the ABMS 103 an ABR Inquiry message(i.e. an ABR message with an Account-Balance-Action AVP field set to 5).

In step 507 the ABMS 103 on receipt of the ABR Inquiry message examinesthe indicated user's account to determine the balance of the account.

In step 509 the determined balance of the account is transmitted fromthe ABMS 103 to the OCF 151 in an ABA message.

In step 511 the determined balance is transmitted from the OCF 151 tothe NE 51 in a CCA message.

Finally in step 513 the determined balance is transmitted from the NE tothe UE 2 in a balance response message. The determined response can thenbe displayed on the UE for the user.

With respect to FIG. 7, a further example of the present invention isshown. In this example the usage of the service provided is at leastpartially subsidised by the operator or a third party and therefore arefund is payable into the users account. One example of which would bethe situation where the operator sponsors a loyalty bonus scheme forexample a “buy 10 minutes of video receive 1 euro of credit to youraccount” incentive scheme.

In step 601 the UE 2 requests a service by transmitting a servicerequest message to the NE 51.

In step 603 the NE 51 determines that the requested service is entitledto a refund as the usage of the service is sponsored.

In step 605 the NE 51 then transmits to the OCF 151 a CCR Event/Refundmessage, in other words the CCR message contains an indication that arefund is to be paid into the user's account.

In step 607 the OCF 151 transmits to the ABMS 103 an ABR Increasemessage (i.e. an ABR message with an Account-Balance-Action AVP fieldset to 6). The message contains the details of the amount to be refundedto the user's account.

In step 609, once the ABMS 103 has received the ABR Increase message theABMS 103 increases the balance of the user's account by the indicatedcredit value.

In step 611, once the ABMS 103 has successfully increased the user'saccount the ABMS then transmits to the OCF 151 an ABA message to confirmthis action was successful.

In step 613, on receipt of the ABA message the OCF 151 transmits to theNE 51 a CCA message to confirm at the NE 51 that the action wassuccessful.

In further embodiments of the present invention the OCF 151 on receiptof the CCR event/refund message can further check to determine if theuser's account is to be refunded or not. The further embodiment step(not shown in FIG. 7) can be used as a secondary check againstfraudulent attempts to receive account recharging.

With respect to FIG. 8 a further example of an embodiment of the presentinvention is shown. The example shown in FIG. 8 is where the servicerequested by the user is a fixed fee service. One example of which couldbe a system whereby items such as transport tickets are purchased usingthe prepay facility on a mobile phone.

In step 701 the UE transmits to the NE 51 a service request.

In step 703 the NE on receipt of the request calculates the chargeassociated with the request.

In step 705 the NE 51 transmits to the OCF 151 a CCR Event/Direct Debitmessage. This message contains the calculated charge.

In step 707 the OCF 151 rates the amount of units used and wherenecessary if it has not been done previously changes the charged unitsinto credits (which in the above examples have been monetary credits).

In step 709 the OCF 151 transmits to the ABMS 103 an ABR Decreasemessage (i.e. an ABR message with an Account-Balance-Action AVP fieldset to 7). The decrease message contains the rated credit value by whichthe user's account is to be decreased.

In step 711 the ABMS 103 decreases the user's account by the valuewithin the ABR decrease message. This operation of decreasing theaccount differs from the steps described in the previous examples asthere is no reservation made on the account.

In step 713 the ABMS then transmits an ABA message to the OCF 713 toconfirm that the request was successfully carried out.

In step 715 the ABMS then transmits a CCA message to the NE 51 toconfirm at the NE 51 that the request was successfully carried out.

Therefore it can be seen with reference by the examples described abovethat the account balance management server 103 can in combination withthe charging and rating server (CRS) 101 carry out a wide range of online charging management operations. Furthermore as the ABMS 103 and theCRS 101 have a well defined range of communications it is possible toincorporate an online charging account management system into part of acentralised account handing system capable of handling both on-line andoff-line account requests and therefore overcoming the problem ofduplication of accounts. Furthermore such a system allows an operator toemploy a much greater flexibility of account operation, such as offeringthe user a single combined (online and offline) account which can havethe advantage of being used by the user to produce an almost instantbalance inquiry.

In further embodiments of the present invention the request and answermessages sent between the CRS 101 and the ABMS 103 (which for theprevious examples described above are ABR and ABA messages) are insteadbased on existing Diameter base messages.

In other embodiments of the present invention the request and answermessages are diameter credit control request and diameter credit controlanswer messages respectively.

Various modifications to the described embodiments will be understood byone skilled in the art. The scope of protection afforded by theinvention is defined by the appended claims.

1. An online charging management server comprising: first receivingmeans configured to receive at least one account request messagetransmitted from a network service provider; and transmitting meansconfigured to transmit an online account balance message to a furtherseparate server based on a received account request.
 2. A server asclaimed in claim 1 wherein the online account balance message is anonline account balance request message.
 3. A server as claimed in claim2 wherein the online account balance request message comprises a requestfor at least one of: Make a reservation; Commit reservation and make newreservation; Commit reservation; Release reservation; Balance query;Increase balance; and Decrease balance.
 4. A server as claimed in claim1, wherein the first receiving means are further configured to receivean incoming online account balance message from the further server.
 5. Aserver as claimed in claim 4, wherein the incoming online accountbalance message from the further server is an online account balanceanswer message.
 6. A server as claimed in claim 5, wherein the onlineaccount balance answer message comprises a value based on the onlineaccount balance request message.
 7. A server as claimed in claim 4,wherein the online account balance message is a Diameter message.
 8. Aserver as claimed in claim 7, wherein the online account balance messageis a Diameter credit control message.
 9. A server as claimed in claim 1,wherein the server is a rating server.
 10. An online charging accountmanagement server comprising: receiving means configured to receive anonline account balance message from at least one further separateserver, the online account balance message based on a received accountrequest message transmitted from a network service provider; andprocessing means configured to perform an online account balance actionbased on the online account balance message.
 11. A server as claimed inclaim 10, further comprising transmitting means configured to transmitan outgoing online account balance message to the further server.
 12. Aserver as claimed in claim 11, wherein the outgoing online accountbalance message is an online account balance request message.
 13. Aserver as claimed in claim 12 wherein the online account balance requestmessage comprises a request for at least one of: Make a reservation;Commit reservation and make new reservation; Commit reservation; Releasereservation; Balance query; Increase balance; and Decrease balance. 14.A server as claimed in claim 11, wherein the outgoing online accountbalance message transmitted to the further server is an online accountbalance answer message.
 15. A server as claimed in claim 14, wherein theonline account balance answer message comprises a value determined bythe processing means based on the online account balance action.
 16. Asystem comprising: the online charging management server as claimed inclaim 1; and a separate online charging account management server, saidonline charging account management server comprising second receivingmeans configured to receive the online account balance message from atleast one further separate server, the online account balance messagebased on the account request message transmitted from the networkservice provider; and processing means configured to perform an onlineaccount balance action based on the online account balance message. 17.A method for performing online charging within a communications networkcomprising an online charging management server and a separate onlinecharging account management server, the method comprising the steps of:receiving at the online charging management server at least one accountrequest message transmitted from a network service provider; andtransmitting from the online charging management server to the separateonline charging account management server an online account balancemessage based on the account request message.
 18. A method as claimed inclaim 17, further comprising the steps of: receiving at the separateonline charging account management server the online account balancemessage; and performing at the separate online charging accountmanagement server at least one account management function based on theonline account balance message.
 19. A method as claimed in claim 18wherein the method further comprises the step of transmitting from theseparate online charging account management server to the onlinecharging management server an additional online account balance messagebased on the step of performing the at least one account managementfunction.
 20. A computer program embodied on a computer readable mediumconfigured to carry out a method for performing online charging within acommunications network comprising an online charging management serverand a separate online charging account management server, the methodcomprising the steps of: receiving at the online charging managementserver at least one account request message transmitted from a networkservice provider; and transmitting from the online charging managementto the separate online charging account management server an onlineaccount balance message based on the account request message.
 21. Acomputer program as claimed in claim 20, further configured to carry outthe steps of: receiving at the separate online charging accountmanagement server the online account balance message; and performing atthe separate online charging account management server at least oneaccount management function based on the online account balance message.22. A computer program as claimed in claim 21, further configured tocarry out the step of transmitting from the separate online chargingaccount management server to the online charging management server anadditional online account balance message based on the step ofperforming the at least one account management function.
 23. A combinedonline and offline charging server comprising: an online chargingaccount management server comprising: receiving means configured toreceive an online account balance message from at least one furtherseparate server, the online account balance message based on a receivedaccount request message transmitted from a network service provider; andprocessing means configured to perform an online account balance actionbased on the received online account balance message; and an offlinecharging account management server.